JPS62127393A - Coal slurry stabilizer - Google Patents

Abstract

PURPOSE:To obtain a coal slurry stabilizer capable of improving the storage stability and flow property of a coal-water slurry, by suspending a grinding or attriction product of a natural or artificial clay mineral. CONSTITUTION:A coal slurry stabilizer contg. a clay mineral component as its major component is produced by grinding or attriting a natural or artificial clay mineral (e.g., montmorillonite) with a dry ball mill or the like to obtain a mineral material, suspending the mineral material in water to obtain an aq. suspension, adding an alkaline earth metal compd. (e.g., NaOH) to the suspension to adjust its pH to 8-9, thereby causing quartz and other substances to precipitate and concentrating the supernatant of the suspension.

Description

[Detailed Description of the Invention] 3. Critical Description of the Invention [Field of Industrial Application] The present invention intends to improve the fluidity and storage stability of a fluid fuel produced as a coal-water slurry. The present invention relates to a stabilizer for coal slurry used in the production of coal water slurry.

[Conventional technology]

In order to produce a coal-water slurry, in addition to the raw materials coal and water, a dispersant that disperses coal particles, a dispersant that functions to disperse rice ash contained in the coal, and a breast ash slurry are also required. Research into numerous types of additives, including thickeners to improve the storage stability of slurry, antifoaming agents to suppress air bubbles generated during manufacturing, and preservatives to prevent slurry from spoiling. Development and practical application are being confirmed. On the other hand, in the production of carbonaceous slurries, chemicals such as acids and alkalis are also used to adjust the dispersant function, prevent corrosion of equipment, etc.

As mentioned above, in the production of coal-water slurry, various substances are being developed to suit different purposes, but the reality is that they are not yet in a satisfactory state as a function of price and resource quantity.

[Problem that the invention seeks to solve]

Nowadays, there is a strong demand for additives that can improve the fluidity of coal-water slurry and improve its stability during storage.

Conventionally, this yuzu test force 11 agent is called a thickener, and mostly polysaccharides and processed products thereof have been used.

Typical examples include guar gum, xanthan gum,
Calhoquine methylcellulose and the like are said to be effective. For these substances, deterioration due to decomposition and other factors does not pose much of a problem for a short period of time after production, but over a long period of time, these problems cannot be ignored, and for this reason, it becomes necessary to use preservatives, etc. Teguru.

Unlike the thickeners mentioned above, this is a new additive that has a thickening effect but does not have to worry about spoilage due to bacteria, etc.
Among clays, which are inorganic compounds, a method using attapulgite, a method using electrostatically precipitated ash (EP ash), etc. are shown.

Regarding these issues, attapulgite has disadvantages such as the fact that its properties are uneven even in the world, and EP ash has difficulties in controlling its properties.

〔the purpose〕

From the experience of the present inventors in preparing coal-water slurry using various types of coal, we have learned that some coals have a strong influence of ash in the slurry state and influence its rheological properties, while others have a relatively weak influence of ash and coals It was found that there are two types of coal that exhibit the rheological properties of the particles themselves. Typical coal brands are Taiheiyo Coal and Wanbo Coal for the former, and Sakun Beer Coal and Plateau Coal for the latter.

From the experience of the present inventors, we have found that coal with a strong ash content, such as Pacific coal, requires additives that increase the fluidity of the ash content.
11 can be controlled by using polycarboxylic acid, polyphosphoric acid, etc. On the other hand, in the case of coal such as Saxon Bale coal, which has a weak influence of ash content, it is necessary to improve the fluidity of the slurry by thickening or the like in order to maintain its storage stability.

In tests conducted by the present inventors, we used an aqueous solution containing fine mineral matter obtained by hot oil granulation to convert slurry with a strong ash content, such as Pacific coal, to coal with a low ash content, such as Saxon Bale coal. The water slurry that was prepared was a highly stable slurry that had a higher apparent viscosity in the low rubbing speed range than the coal water slurry prepared using city water. From various studies conducted to find the cause of this, it was found that one of the reasons is that when clay powder is dispersed in colloidal form, if it exists in a certain amount or more, it affects the rheology of the slurry. . Based on this situation, we have completed the present invention as a result of repeated studies on identifying substances that can control the rheological properties of coal-water slurry and methods for adjusting them. That is, the purpose of the present invention is to
Another object of the present invention is to provide a stabilizer for coal slurry that can improve the fluidity of coal water slurry and improve the stability during storage. It is an object of the present invention to provide a stabilizer for coal slurry that can improve the fluidity necessary for coal-water slurry for coal whose ash content is weakly affected.

[Means for solving problems]

Therefore, the present invention, as a means to achieve the above object, consists in using an aqueous suspension of clay minerals as a stabilizer for coal slurry. Namely.

Undeveloped BA is an aqueous clay mineral suspension solution in which crushed or ground natural or artificial clay minerals are suspended in water.)
This stabilizer for coal slurry is characterized by:

As the stabilizer for coal slurry of the present invention, any clay mineral that can be suspended in water as a colloid by dispersion is effective. Incidentally, it is desirable that the particle size of the colloidal clay mineral be approximately 2 μm or less. Typical examples include alkaline clay minerals such as montmorillonite, hectorite, and attapulgite alone or in mixtures thereof, clay minerals containing these as main components, and acidic clay mineral kaolinite.

Any other material may be used as long as it provides a suspension of minute clay particles; for example, minerals containing halloysite, sericite, etc. are also effective.

In the present invention, although the above-mentioned suspended aqueous solution of clay minerals is used, a concentrate obtained by separating clay minerals from this M turbid aqueous solution can be used, and during this separation,
It is preferable to add an alkaline earth metal compound, for example, a compound of calcium, magnesium, etc., and to separate the clay mineral concentration in the coexistence of this compound, and to use a mixture that is brought to zero.

This is to replace alkaline ions such as sodium and potassium contained in clay minerals with alkaline earth metals such as calcium and magnesium. It is particularly important to reduce the content of alkali metals.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

(Example 1) Bentonite containing montmorillonite as a main component is
It is also commercially available as a soil conditioner in our country. This commercially available bentonite was finely pulverized using a dry ball mill, and the bentonite was collected to form an aqueous solution of about 10% based on air-dried bentonite. First, in order to facilitate the dispersion operation, this bentonite was diluted with -18 to -18 Trowel adjusted to 9 and made into a paste with hydrotactic solution, NaOH, KOH or N
Quartz and other substances contained in bentonite suspended in a -8 to 9 dilute alkaline aqueous solution prepared with H4OH
Sediment the jM and make a suspension of the supernatant! I did 1ilF. The particle size of the solid content in the suspension at this time is 63.3% of 2 μ or less.
Atatsu nine. Also, the clay mineral concentration in this suspension is 800C
It was determined by the amount remaining after ashing and firing.

When preparing a coal-water slurry with a coal concentration of 65X, which is produced using pulverized Saxon Bale coal from Suizhou and the anionic additive sodium salt of naphthalene sulfonic acid formalin condensate (NSF-Na) y2, the above-mentioned suspension is used. The results are shown when the liquid was used in combination. Figure 1 shows a comparison of rheology measurement examples for a coal-water slurry in which a suspension was added after adjusting the ash concentration to 0.2X, and a coal-water slurry without any additives. . In FIG. 1, curve (1) shows the rheology of the slurry with additives, and curve (2) shows the rheology of the slurry without additives. From the comparison of both lines in Figure 1, the effect of the addition is to increase the viscosity of the slurry without significantly increasing the hysteresis (size of the area within the graph), which is shown by the difference between the up and down rheology curves. It is. This thickening effect results in good storage stability of the slurry. These prepared slurries were stored in glass cylinders, and the deposition status of coal particles was tracked and compared using the rod penetration method. The results are shown in Table 1. The addition of suspended clay particles stabilized the storage of the coal-water slurry. It is clear that it contributes to

Table 1 Relationship between sediment layer formation rate and standing period (unit: %) (Example 2) The bentonite suspension layer obtained in the operation of Example-1 was centrifuged. We will explain an example in which the effectiveness of clay particles was confirmed by using them after being concentrated. The purpose of this operation was to confirm the concentration operation to facilitate handling as a stabilizer, and to convert alkali metal ions such as sodium and potassium contained in the clay particles into alkaline earth metals such as calcium and magnesium. exchange,
This is expected to have the effect of reducing the content of undesirable alkali metals in fuel additives.

Calcium hydroxide is added to the supernatant liquid to a concentration of 10% to replace the alkali metals in bentonite with alkaline earth metals, and then separated by centrifugation, and the precipitate is processed as a water-containing paste. Example-1 using the
A water slurry of Saxon Pale coal was prepared in the same manner as above, and its storage stability was investigated. The results are shown in Table 2.

It is clear that the stability is improved compared to the additive-free slurry shown in Table 1. Almost the same results as those obtained with calcium were obtained with magnesium salts or mixtures of calcium and magnesium, which are alkaline earth metals other than calcium.

Table 2 Relationship between sediment layer formation rate and standing period (Example 5) Joshia kaolin was used as an example of kaolinite mineral whose grinding is acidic, and it was prepared in the same manner as in Example 1.
Table 3 shows the storage stability test results for prepared Plateau carbonate slurry with and without addition, and the effect of addition was confirmed in the same manner as in Example-1.

Table 5 Relationship between sediment layer formation rate and standing period (Example 4) The bentonite suspension supernatant obtained in Example-1 was separated by centrifugation* After concentration, at 105C for 4 hours It was dried to obtain a solid content. This solid content is 800C
The weight loss after drying at high temperature was between 85 and 90% of the original sample.

As a guideline for the remaining amount after drying at high temperature, a storage test of CWM was carried out by adding the CWM to the water concentration shown in Table 4 after CWM production. Comparing the results to the case without additives,
As shown in Table i4, it is clear that even if the clay particles are taken out as a solid content and used, there is an effect on the storage stability of the slurry.

Table 4 Relationship between sediment layer formation rate and standing period As shown in Examples 1 to 3 shown above, fine clay mineral powder prepared by crushing and suspending operations is effective in stabilizing coal-water slurry. It was confirmed that it is an effective substance.

〔effect〕

As described in detail above, the present invention is capable of producing clay minerals by adding to coal slurry 17- a clay mineral suspension in which crushed or ground natural or artificial clay minerals are suspended in water. This has the remarkable effect of improving the fluidity of the coal slurry and improving its stability during storage.

[Brief explanation of drawings]

FIG. 1 is a diagram showing rheology measurement results when a clay mineral suspension was added to the coal-water slurry (curve 1) and when no clay mineral suspension was added (curve 2). Sub-Agents 1) Akira Agent Ryo Hagiwara - Sub-Agent Atsuo Anzai, +001 7wITT: no 廿ω ding ('Ura II (+!F Shoken 161 i, 3) 13/1j Commissioner of the Japan Patent Office n' Uga Michibu, 1.i2), first year of junior high school ('shi) entry, Showa 60 K11, 1st application No. 266197, 3) Relationship with old 1'' to f'1, which stops the mountain 1, 'out, 'Qf+person II
・Su [2-5-1-4 Marunouchi, Chiyoda-ku, Tokyo, Fukudai 11"□I [Toramon-cho, Minato-ku, Totaku] 116-2 Shiji5
, N+1ijlE order order. . Ej, spontaneous correction
("'Detailed Description of the Invention' of the Phantom Specification, Column A, Contents of Amendment, ii1, page 6, "NoOHJ" is corrected to "NaOHJ.

Claims (3)

[Claims] (1) A stabilizer for coal slurry comprising an aqueous clay mineral suspension solution in which a crushed or ground natural or artificial clay mineral is suspended in water. (2) The stabilizer for coal slurry according to claim 1, which contains as a main component a composition of clay minerals separated and concentrated from an aqueous suspension of clay minerals. (3) The first claim is characterized in that the main component is a clay mineral composition that is separated and concentrated from an aqueous suspension of clay minerals after coexisting with an alkaline earth metal compound in an aqueous suspension of clay minerals.
The stabilizer for coal slurry according to item 1 or 2.